In the name of God

Osteomalacia

Mohsen Mardani-KiviAssistant Professor, Orthopedic Department, Guilan University of Medical Sciences

Case• 33 year old Asian lady• Presents with 3 /12 months history of

generalised bony pain• PMH depression• D/Hx sertraline• P/Ex generalised bony tenderness• Joints normal ROM, no inflammation

Investigations• Hb 12.9 (11.5-16.5) Calcium 2.18 (2.2-2.6)

• WBC 4.7 (4.9-11.0) Phosphate 0.79 (0.85-

1.45)

• Plt 253 (150-400) Albumin 39 (35-50)

• ESR 12 Alk Phos 172 (25-96)

• Clotting Normal Total protein 72 (60-80)

• Urea 4.2 (3.0-6.5) LFTs normal

• Creat 85 (35-120)

• Diagnosis?

Definition• Osteomalacia is the general term for the

softening of the bones due to defective bone mineralization.

Definition• Osteomalacia in children is

known as rickets, and because of this, it is often restricted to the milder, adult form of the disease.

• It may show signs as diffuse body pains, muscle weakness, and fragility of the bones.

General characteristics

• Osteomalacia is derived from Greek: – osteo bone– malacia softness

• most commonly found in:– dark-skinned– diet-disbalanced subjects (mainly lactating females).

• Age: adults• Site: WEIGHT-BEARING BONES such as vertebral

bodies and femoral neck

General characteristics

Physiology Normal bone metabolism: CA

• CALCIUM 99% in bone. • Main functions muscle /nerve function, clotting.• Plasma calcium 50% free, 50% bound to albumin. • Dietary needs:

– Kids: 600mg/day– Adolescent 1300mg/day,– Adult: 750mg/day– Pregnancy: 1500mg/day, – Breastfeeding: 2g/day,– Fractures: 1500mg/day

• Absorbed in duodenum (active transport) and jejunum (diffusion), 98% reabsorbed in kidney prox. tubule, may be excreted in stool.

Physiology Normal bone metabolism: PHOSPHATE

• PHOSPHATE 85% in bone.• Functions: metabolite and buffer in enzyme systems.• Plasma phosphate mainly unbound.

Daily requirement: 1-1.5g/day

Physiology Regulation of Calcium & Phosphate Metabolism:Peak bone mass at 16-25 years.Bone loss 0.3- 0.5% per year (2-3% per year after 6 th decade).1. Parathyroid Hormone (PTH)2. Vitamin D33. Calcitonin4. Other Hormones:

Estrogen: Prevents bone loss Corticosteroids: Increases bone loss Thyroid hormones: Leads to osteoporosis Growth hormones: Cause positive calcium balance Growth factors

http://www.orthoteers.co.uk/Nrujp~ij33lm/Images2/metab3.jpg

Physiology

Physiology

Physiology • Serum Ca & Phosphate in equilibrium with Ca & Phosphate

in bone.

Physiology

Patho physiology

Kidney disease

Defect in phosphateexecration

No hydroxylation of Vit.D3

Patho physiology

Hypocalcaemia So,Stimulation of PTH

Bone..Relase of Ca.

Kidney Ca absorption

Etiology• Calcium deficiency

– Hypo-phosphataemia– Defect in Vitamin D metabolism

• Nutritional– Diet: oily fish, eggs, breakfast cereals– Antacid abuse, causing reduced dietary phosphate

binding

• underexposure to sunlight– Elderly individuals with minimal sun exposure– Dark skin, skin covering when outside

Etiology• Calcium deficiency

– Hypo-phosphataemia– Defect in Vitamin D metabolism

• intestinal mal-absorption– Coeliac– Intestinal bypass– Post-Gastrectomy– Chronic pancreatitis– Biliary disease (reduced absorption of Vitamins)– Small bowel disease

• Calcium deficiency– Hypo-phosphataemia– Defect in Vitamin D metabolism

• liver & kidney diseases – Fat mal-absorption syndromes – Kidney failure: RTA, Renal osteodystrophy

• Epilepsy: phenytoin, phenobarbitorate• Genetic disease

Etiology

• Other Etiologies:– Receptor Defects– Altered phosphate homeostasis

Etiology

Pathology

Symptoms & Signs• Bone pain , backache• Muscle weakness• Vertebral collapse: kyphosis• loss of height• Deformities & stress fractures

• Osteomalacia in adults starts insidiously as aches and pains in the lumbar region and thighs, spreading later to the arms and ribs.

• Pain is non-radiating, symmetrical, and accompanied by tenderness in the involved bones.

• Proximal muscles are weak, and there is difficulty in climbing up stairs and getting up from a squatting position

Symptoms & Signs

• Physical signs include deformities like lordosis.• Pathologic fractures due to weight bearing may develop.• Most of the time, the only alleged symptom is chronic and

bony ache which is only revealed by pressure or shocks.

Symptoms & Signs

• Rickets – Tetanus , convulsions, failure to thrive– restlessness, muscular flaccidity– Flattening of skull (craniotabes)– Thickening of wrists from epiphyseal overgrowth, Stunted growth,

Rickety rosary, spinal curvature, Coxa vara, bowing, – Fx of long bones

• Osteomalacia– Aches and pains– muscle weakness loss of height– stress fx

Symptoms & Signs

1.Hypo-calcaemia

2.Hypo-calcuria

3.High alkaline phosphatase

biochemistry

Work up for OsteomalaciaWork up for Osteomalacia

Ca , P , Alk ph 24 h urinary Ca 25 (OH) Vit-D 1 , 25 (OH) Vit-D PTH Bone Biopsy

biochemistry

1- ca P = Nl Alk ph2- ca = Nl P Alk ph3- ca P Alk ph

24 h Urinary ca < 100 mg / 24 h24 h Urinary Hydroxyproline Excretion

biochemistry

*Rickets - Growth plate widening & thickening

- Metaphyseal cupping

- Diaphyseal deformities

*Osteomalacia - Looser zone , biconcave vertebra , protrusio acetabuli

- Spontaneous fractures

*Signs of secondary hyperparathyroidism

X-ray

Loosers zones – incomplete stress Fx with

healing lacking calcium, on compression side of long bones. 

Codfish vertebrae due to pressure of discs

Trefoil pelvis, due to indentation of acetabulae stress fx

X-ray

Loosers zones

X-ray

X-ray

X-ray

Depends on the cause

Nutritional Vitamin D deficiency Dietary chelators of calcium

Phytates

Oxalates Phosphorus deficiency (unusual)

Antacid abuse

Treatment

Depends on the causeGastro-intestinal absorption defects

Post-gastrectomy Biliary disease Enteric absorption defects

Short bowel syndrome Rapid onset (gluten-sensitive enteropathy)

Inflammatory bowel disease Crohns Celiac

Treatment

Depends on the causeRenal tubular defects

Vitamin D dependant type I type II Treatment; High levels of vit D

Vitamin D resistant (familial hypophosphatemic rickets) Treatment; Phosphate 1-3 gm daily, Vit D3 high dose

Fanconi syndrome I, II, III Renal tubular acidosis

Treatment

Depends on the cause

Renal Osteodystrophy – in chronic renal failure

Miscellaneous Hypophosphatasia Anticonvulsant therapy

SURGERY

For deformities

Treatment

Treatment

• Natural sources cheese, sardines, salmon, dark leafy vegetables & sesame seeds.

Treatment